Grasshopper invasion possible across Southwest

While no one is willing to say the sudden appearance of large numbers of grasshoppers in and around Albuquerque is sounding an alarm for New Mexico agriculture, many admit it could be cause for concern.

While no one is willing to say the sudden appearance of large numbers of grasshoppers in and around Albuquerque is sounding an alarm for New Mexico agriculture, many admit it could be cause for concern.

Bernalillo County Cooperative Extension Service officials and local nurseries report numerous calls from concerned residents about a flood of grasshoppers that have been showing up in parts of the city and county in large numbers in recent days. Most of the callers are concerned about the possibility of damage that could come to their outdoor plants.

And it's not just residents complaining about the swarms of pesky hoppers. Businesses and public works crews are complaining that some areas are so riddled by the arriving grasshoppers that they can populate sidewalks, roads, driveways and porches, making it impossible to avoid stepping or driving across large numbers of the pesky green invaders and making clean up a major and unpleasant task.

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Cheryl Kent, an Extension Service horticulture specialist, says an increase in the number of grasshoppers is not unusual and generally is caused by a combination of factors. Following an extended summer drought like last year, substantial rains last fall, a mild winter and warming temperatures this spring have probably all contributed to a spike in the number of grasshopper eggs hatching this year.

Favorable conditions

She says the arrival of such large numbers are probably the result of favorable conditions that led to a population explosion, and that can be troubling for homeowners and nurseries because grasshoppers can defoliate trees and shrubs and can wreak havoc in gardens rather quickly.

Entomologists say most grasshopper species in the U.S. occur in semi-arid environments, and it is in the warm semi-arid grasslands and shrub lands that grasshopper species diversify and where population densities are greatest. Laying their eggs in the soil in the autumn, late season wet conditions can help those eggs survive cooler weather and hatch once soils warm again in spring.

Officials at the Albuquerque Environmental Health Department say the grasshoppers pose little threat to human health but historically have plundered rich rangelands not only in New Mexico but all across the West and as far as Oregon and Washington State in the Northwest.

USDA reports that in the mid-1980s grasshoppers were responsible for consuming large swaths of grasslands and crops across parts of the West, a tragedy that has been reported many times down through the years. In fact, since antiquity, grasshoppers have been recognized as sporadically severe pests of crops and grazing areas across the Western United States.

The Navajo of the desert Southwest accurately observed that grasshopper outbreaks were often associated with drought, and USDA says things haven't changed that much down through the years.

USDA's Animal and Plant Health Inspection Service (APHIS) conducts surveys for grasshopper populations on rangeland in the Western United States, provides technical assistance on grasshopper management to landowners and managers, delivers public outreach and education programs, and may assist to suppress grasshopper populations when direct intervention is necessary.

In some cases, APHIS rangeland treatments protect not only the rangeland but also

reduce the likelihood that the grasshoppers will move into crops and other lands that border rangeland.

USDA officials last week said they were just beginning to hear reports of large grasshopper populations cropping up in limited areas in northern New Mexico and will monitor reports from state agriculture and Extension officials.

In the meantime, Albuquerque officials and Extension agents are recommending that homeowners and nursery operators cover unprotected plants—the best way to ward off damage. They say effective chemical alternatives are available if conditions warrant.

For more information about the threat posed by grasshopper and how to treat outbreaks, visit the New Mexico State University grasshopper website.